A RNA differential display analysis was performed using RNAs from the liver tumor cell lines SK-HEP-1, HEP-G2 and HEP-3B, as well as normal liver RNA. Promising bands were eluted from the gel and molecularly cloned. About 20 clones were confirmed to correspond to genes that are differentially expressed among the different RNA sources by RNA gel (Northern) blotting. Probing multiple tissue Northern (MTN) blots revealed that several of these genes have limited expression in normal tissues. They may be useful in the study of the biology of liver cancer or may be potential markers for this disease.